Furbeast, you are, of course, correct, all genuine scholarship being on your side. I did, however, want to mention an Anglo-Saxon folk etymology - Surly an' A Lot. These come up when simple beans put their heads together and try to figure out the origin or original sense behind words or names they no longer understand or never understood. Of course, better educated beans (those who sneak around and listen to their bunns) would immediately realize that, as a name, Sir Lancelot speaks for itself and is quite apropos here given its reference to a long time trouble maker.